The compounds of this invention exhibit V.sub.1 and/or V.sub.2 vasopressin antagonist activity. Vasopressin is known to contribute to the antidiuretic mechanism of actions within the kidney. The action of these compounds antagonizes that of the natural anti-diuretic hormone (ADH) so as to cause the body to excrete water.
M. Manning et al., (9th American Peptide Symposium,) pp. 599-602, disclosed that replacement of glycineamide with tyrosineamide in the full tripeptide tail, i.e. Pro-Arg-GlyNH.sub.2 produced compounds which exhibit vasopressin antagonist activity.
U.S. Pat. Nos. 4,481,193 and 4,481,194 have disclosed that removing proline at position 7 or both proline and glycine at positions 7 and 9 from the structures of vasopressin antagonist compounds produced compounds which retain substantial, but somewhat reduced, antagonist activity.
U.S. Ser. No. 877,571, filed June 23, 1986 disclosed vasopressin-like antagonists which contain two basic amino acid units, such as arginine or lysine, which are attached directly to the cyclic disulfide vasopressin-like ring.
The compounds of this invention have structures which are distinguished over the prior art in that a combination of a neutral and a basic amino acid unit, such as tyrosine and arginine, are directly attached to the cyclic disulfide vasopressin-like ring. The compounds of this invention are potent vasopressin antagonists.